Thermodynamics
Steam burns are more damaging than burns caused by boiling water because steam
Choices A & B are both correct (has more energy per kg than boiling water, gives up additional energy when it condenses)
Heat energy is measured in units of
Choices A & B are both true (calories and joules)
Substances absorb heat energy by the process of
all of these (conduction, convection, radiation)
If you were caught in freezing weather with only a candle for heat, you would be warmer in
an igloo
Consider a metal ring with a gap cut in it. When the ring is heated, the gap
becomes wider
A liter of hot water will cool to room temperature faster in a
black pot
Cold water will warm to room temperature faster in a
black pot
If you want to cook eggs by boiling them while on the mountains, then compared to sea-level cooking, you should
boil the eggs for a longer time
Newton's law of cooling applies to objects that are
both of these (heating, cooling)
When mechanical work is done on a system, there can be an increase in
both temperature and internal energy
The first law of thermodynamics is a restatement of the
conservation of energy
Melting snow
cools the surrounding air
Ice is put in a cooler to cool the contents. To speed up the cooling process, the ice can be
covered with salt
As a piece of metal with a hole in it cools, the diameter of the hole
decreases
When heat is added to boiling water, its temperature
does not change
Hot water has a relatively high rate of
evaporation
Wrapping a hot potato in aluminum foil significantly reduces the rate at which it cools by
evaporation
A substance can be sprayed on crops to prevent frost formation under many conditions. If frost did not form on the fields and wood of an entire continent, cold nights would be
even colder
When water at 4 degrees C is heated it expands. When water at 4 degrees C is cooled, it
expands
When you touch a cold piece of ice with your finger, energy flows
from your fingers to the ice
A good absorber of radiation is a
good emitter of radiation
An adiabatic process is characterized by the absence of
heat exchange
Food in a pressure cooker is cooked faster because of the
higher temperature
Compared to a giant iceberg, a hot cup of coffee has
higher temperature, but less internal energy
In a mixture of hydrogen gas, oxygen gas, and nitrogen gas, the molecules with the greatest average speed are those of
hydrogen
If you run a refrigerator in a closed room with the refrigerator door open, the room temperature will
increase
Suppose you rapidly stir some raw eggs with an eggbeater. The temperature of the eggs will
increase
When a volume of air is compressed, its temperature
increases
One of the main reasons one can walk barefoot on red-hot coals of wood without burning the feet has to do with
low thermal conductivity of the coals
Suppose you want to save energy and you're going to leave your cool house for a half hour on a hot day. You should turn the temperature setting on the air conditioner
off altogether
When a gas is changed to a liquid state, the gas
releases energy
Evaporation is a cooling process and condensation is
a warming process
When a solid is changed to a liquid state, the solid
absorbs energy
The lowest temperature possible in nature is
-273 degrees C
A volume of air has a temperature of 0 degrees Celsius. An equal volume of air that is twice as hot has a temperature of
273 degrees C
Before ice can form on a lake, all the water must be cooled to
4 degrees C
The fact that desert sand is very hot in the day and very cold at night is evidence that sand has
a low specific heat
A refrigerator
removes internal energy from inside the refrigerator
If you stake a plot of land with a steel tape on a very hot day, the actual amount of land you will have will be
smaller than measured
The white-hot sparks that strike your skin from a 4th-of-July-type sparkler don't harm you because
the energy per molecule is high, but little energy is transferred because of the few molecules in the spark
A water-filled paper cup held in a flame will not catch fire. This is because
the paper cup cannot become approx. hotter than the water it contains
The fact that a thermoeter "takes its own temperature" illustrates
thermal equilibrium
Consider a closed, sealed can of air placed on a hot stove. The contained air undergoes an increase in
two of these (pressure, temperature)
During a very cold winter, water pipes sometimes burst. The reason for this is
water expands when freezing